Valve mechanism



June 4, 1946. H, WILLIAMS 2,401,716

VALVE MECHANISM Filed Dec. 16, 1943 & a

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x Her-E HEM. i L I A TTO/PNE Y$ 1 Patented June 4, 1946 VALVE MECHANISM Herbert J. Williams, Elyria, Ohio, assignor to Behdix-Westinghouse Automotive Air Brake Company, Elyria, ware Ohio, a corporation of Dela- Application December 16, 1943, Serial No. 514,538

4 Claims.

This invention relates to fluid pressure control mechanism, and more particularly to valve mechanism for controlling fluid pressure systems.

One of the objects of the invention is to provide a novel fluid pressure control valve mechanism f the self-lapping type wherein a more compact arrangement of the parts is obtained than has been the case with previous constructions.

Another object of the invention is to provide means for mounting the graduating spring of a valve of this type on the brake pedal.

Yet another object of the invention is to provide novel means for transmitting force from the brake pedal to the valve operating mechanism through a graduating spring mounted on the brake pedal.

Still another object of the invention is to provide means for positioning the graduating spring of a brake valve in such a manner that the initial tension of the spring may be readily adjusted by the operator. A still further object of the invention is to provide, in connection with a valve mechanism of the above type having the graduating spring mounted on the brake pedal, simple and efiicient means for providing a direct and non-yielding connection between the brake pedal and valve operating means whenever the force exerted on the spring by the operation of the pedal exceeds a predetermined value.

A further object of the invention is to provide simple and novel means for initially preloading the graduating spring mounted on the brake pedal, as well as simple and accessible. means for adjusting the degree of such preloading.

Other objects and novel features of the invention will appear more fully hereinafter from the following detailed description when taken in connection with the accompanying drawing illustratlve of one form of the invention. It is to be expressly understood, however, that the drawing is utilized for purposes of illustration only and is not designed as a definition of th'elimits of the invention, reference being had for this purposeto the appended claims.

In the drawing wherein similar reference char- 'acters refer to like parts throughout the several views:

Fig. 1 is an axial sectional view of a control valve mechanism constructed in accordance with the principles of the present invention, and

Fig. ,2 is a'fragmentary sectional view of the upper portion of the valve mechanism with the brake pedal in applied position.

Referring more particularly to Fig. 1 of the drawing, the control valve is illustrated as including a casing 4 provided with an inlet chamber 5 adapted to receive fluid under pressure from a supply reservoir 6 through a conduit 1, an outlet chamber 8 adapted to supply fluid pressure to a brake operating cylinder 9 through a conduit ill, a diaphragm chamber I I connected with the outlet chamber 8 by means of a restricted passage I2, and an exhaust chamber I 3 connected with atmosphere by means of an exhaust conduit I 4, the diaphragm and exhaust chambers being separated by means of a suitable flexible diaphragm l5 mounted in the casing as shown. The inlet chamber is separatedfrom the outlet chamber by means of a ported partition IS, the passage of fluid from the inlet chamber through the outlet chamber being normally prevented by means of an inlet valve I! normally maintained in portclosing position by means of a spring l8 interposed between the upper surface of the partition 16 and the lower surface of an exhaust valve l9 connected with the inlet valve by means of a valve stem 20. A valve operating member 2| is suitably clamped to the central portion of the diaphragm as shown, the lower end of the memher being slidably mounted in a sealing element 22 positioned in the upper end of a bore 23 formed in the casing. The upper end of the valve operating member is provided with an upwardly extending tubular extension guided at its upper end by means of a flanged portion 25 in engagement with a shoulder 26 formed at the upper end of an internal bore 21 formed in a valve operating plunger 28, which is slidably mounted for vertical movement in a bore 29 formed in the housing, downward movement of the plunger 28 thus servingto impart downward movement to the member 24 and to the valve operating .member 2|. The valve operating member 2! is provided with a centrally located bore 30 connected at its lower end with the outlet chamber 8 and connected at its upper end with the exhaust valve l3 through the interior of the tubular member 24 and ports 3| formed in the wall of said member. Thus on downward movement of the valve operating member 2|, the upper surface of the exhaust valve engages the lower end of the bore 30 to prevent communication between the outlet and exhaust chambers, further downward movement of the member serving to open the inlet valve in order to permit communication between the inlet chamber 5 and the outlet chamber 8.

In order to provide for operation 01 the valve operating member 2|, a pedal 32 is pivotalli mounted on the upper portion of the casing by means of a pivot pin 33, the same pivot pin having mounted thereon a lever 34 of the bell-crank type having a horizontally extending arm 35 and an upwardly extending arm 36, the left end of the arm 35 being connected with the tubular member 34 attached to the valve operating member by means of a push rod 31 interposed between a socket 38 formed in the lever arm and a similar socket 39 formed in the upper end of a seat member 40 mounted on the upper end of the plunger 28. The upper lever arm 36 is connected with the brake pedal by means of a tension link 4| pivotally connected thereto b means of a pin 42 and extending to the left along the underside of the pedal through a bore 43 formed in an abutment 44 mounted on the pedal. Apair of relatively movable abutments 45 and 46 are slidably mounted on the tension rod, movement of the abutment 45 to the right along the rod being prevented by means of a shoulder 41 formed thereon and movement of the abutment 46 to the left along the rod being prevented by means of a nut ,48

threadedly mounted on the left end of the .rod.

The right face of the abutment 45 is spherically formed and adapted for engagement with a similarly formed socket portion 49 formed in the left surface of the abutment 44, and in order to provide means for transmitting force from the pedal to the link on movement of the pedal relative to the casing, a graduating spring 50 is interposed between the abutments 45 and 46. Thus on movement of the brake pedal in a counterclockwise direction about the pivot pin 33, the abutment 45 is moved to the left along the rod 4| by means of the abutment 44 and the graduating spring is compressed to exert a tension on the rod 4| through the abutment 46 and the nut 48.

When this action occurs, the valve operating member 2| is moved downward through the connections previously described to operate the valves to prevent communication between the outlet and exhaust chambers and permit communication between the inlet chamber and the outlet chamber connected to the brake cylinder. lAS the pressure increases in the outlet chamber 8, this is communicated to the diaphragm chamber through the restricted passage I2, and as soon as the force exerted on the diaphragmis sufficient to balance the downward force exerted on the member 2| by the operation of the brake between the abutment -45 pedal through the above described range, the diaphragm and valve operating member ill be moved upward to compress the graduating spring carried by the brake pedal and to permit closing of the intake valve under the action of the valve spring l8.

It has been found desirable in connection with self-lapping valves of the above described type to provide means for placing the graduating spring in a preloaded or precompressed condition when the brake pedal is in released position, and in the present instance such preloading may be accomplished by adjustment of the nut 48 which serves to move the abutment to the right along theplink 4| in order to'compress the spring between the two abutments, it being noted that with the pedal in released position, movement of the abutment 45 to the right as a result of this precompression is prevented by the shoulder 41 formed on the tension link. With the graduating spring thus preloaded, the connection between the pedal and the valve operating member 2| during initial movement of the pedal is of the non-yielding type, and consequentl the initial pressure delivered valve is measured by the degree of preloading of the graduating spring as will be readily understood by those skilled in the art. It is also desirable in connection with valve mechanisms of this general type to provide means for providing a non-yielding connection between the brake pedal and the valve operating member when the pressure delivered by the valve exceeds a predetermined value, the purpose of this being to permit the operator to maintain the inlet valve in open position in order to supply full reservoir pressure to the brake cylinder regardless of the self-lapping'action normally exerted by the cooperative action of the pressure responsive diaphragm and the graduating. spring, and this desirable function is accomplished in the present instance by means of a tubular spacer 5| mounted on the link 4| and 46 and serving to limit the degree of compression which can be imparted to the graduating spring on downward movement of the brake pedal. This condition is more particularly illustrated in Fig. 2 of the drawing, wherein the brake pedal has been depressed sufficiently to cause the abutment 45 to move to the left along the link 4| to such an extent that further movement is prevented by means of the spacer 5|. Under this condition of operation, it will be ther downward movement of the brake pedal, the latter will be directly and non-yieldingly connected to thevalve operating member and the inlet valve will be maintained in open position.

There has thus been provided by the present invention novel and efllcient means for mounting the graduating spring on the underside of the operating pedal of a self-lapping fluid pressure control valve, so constituted as to avoid interference between the graduating spring and the other parts of the valve and parts of the vehicle, and at the same time permitting ready adjustment of the tension of the graduating spring during initial assembly of the valve as well as when the valve is mounted on the vehicle. The graduating spring is connected with the valve operating means through the tension link and the bell crank lever in such a manner that the spring is always substantially parallel to the upper surface of the pedal, with the result that the spring can be readily concealed from view and protected from injury by the structure of the pedal. It will also be understood that if desired, the upwardly extendin tubular member 24 which serves to connect the valve member 2| with the valve operating plunger 28 can be materially shortenedin order to provide an extremely compact structure, since with the present construction, the graduating spring occupies a space which heretofore did not serve any useful purpose. It has also been customary in connection with previous constructions of this type to compensate for variations in the length of the graduating spring and other parts by means of shims, a procedure which has caused considerable difficulty during initial asfrom the outlet chamber of the Q understood that during fur-- resorted to and certain elements used without others without departing from the spirit of the invention, as is well understood by those skilled in the art. Reference will, therefore, be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. Resilient actuating mechanism for a pivotally mounted lever, said mechanism including an actuating pedal mounted for rotation about the same axis as the lever, a rod having a pivotal connection with said lever, a spring seat slidably mounted on the rod and pivotally connected with the pedal, a second spring seat slidably mounted on the rod and spaced from the first named seat, means carried by the rod for limiting the spacing between the first and second named spring seats, and a compression spring interposed between saidseats, said rod and spring being positioned substantially parallel with said actuating pedal by said first named spring seat.

2. Resilient actuating mechanism for a pivotal- 1y mounted lever, said mechanism including an actuating pedal mounted for rotation about the same axis as said lever, a rod having a pivotal connection with said lever, a spring seat slidably mounted on said rod and pivotally connected with said pedal, a shoulder on said rod for preventing movement of said spring seat along said rod toward said lever beyond a predetermined position, a second spring seat slidably mounted on said rod, a compression spring interposed between said seats, and means carried by said rod for moving the second named seat toward the first named seat for compressing said spring and forcing the first named seat against said shoulder, said rod and spring being positioned substantially parallel with said pedal by said first named spring seat.

3. Resilient actuating mechanism for a pivotally mounted lever, said mechanism including an actuating pedal mounted for rotation about the same axis as the lever, a rod having a pivotal connection with said lever, a spring seat slidably mounted on the rod and pivotally connected with the pedal, a second spring seat slidably mounted on the rod and spaced from the first named seat, means carried by the rod for limiting the-spacing between the first and second named spring seats, a compression spring interposed between said seats, and-a sleeve mounted on said rod between said seats for engaging the latter and providing a non-yielding connection between said pedal and lever when said spring has been compressed a predetermined amount.

l. Resilient actuating mechanism for a pivotal- )y mounted lever, said mechanism including an actuating pedal mounted for rotation about the same axis as said lever, a rod having a pivotal connection with said lever, a spring seat slidably mounted on said rod and pivotally connected with said pedal, a shoulder on said rod for preventing movement of said spring seat along said rod toward said lever beyond a predetermined position, a second spring seat slidably mounted on said rod, a compression spring interposed between said seats, means carried by said rod for moving the second named seat toward the first named seat to compress the spring, and a spacer on said rod between said seats for engaging the latter and providing a non-yielding connection between said lever and pedal when the force exerted on the latter to actuate the lever exceeds a predetermined value.

'HERBERT J. WILLIAMS. 

